Theaflavin-3,3’-digallate is a polyphenolic compound found in black tea. The theaflavins are formed during the enzymatic oxidation of catechins, which happens during processing of the fresh tea leaves. Theaflavin-3,3’-digallate has also shown inhibitory effects on ovarian cancer cells OVCAR-3 and A2780/CP70 by inducing apoptosis and impairing tumor angiogenesis. In addition, theaflavin-3,3’-digallate was found to produce notably efficient reactive oxygen species scavenging activity by a chemiluminescence assay. Theaflavin-3,3’-digallate was also shown to produce chemopreventive effects through the inhibition of the EGFR signaling pathway as a result of EGFR down-regulation.